A new peer-reviewed study by scientists at the National Institute of Immunology and physicians at St. Stephens Hospital in New Delhi, India. found that mothers with a past history of Chickenpox infection [Varicella-Zoster] may transmit Chickenpox viral DNA [Varicella-Zoster IgG] to their babies during pregnancy — thereby stimulating the infants’ immunity against this infection.
Jacob Puliyel, MD* and colleagues from St Stephens Hospital studied 350 mothers and their new-born babies. The findings suggest that this mother-to-child transfer of viral DNA may be responsible for the long-lasting protection against serious chickenpox infection seen during childhood. If replicated, these novel findings will revolutionize the present day understanding of how babies are protected against infections like chickenpox in childhood.
Chickenpox reactivation after surgical stress is known; and scientists have also demonstrated that the stress of space travel can induce subclinical reactivation of chickenpox in astronauts. However, the authors note, that this study is the first to report subclinical reactivation of chickenpox, induced by the stress of pregnancy.
The present understanding is that mothers provide their babies’ protection against a variety of common infections, by transferring ready made antibodies to them. The protection to the baby lasts for 12 to 15 months. If the baby encounters the infection while it is partially protected by maternal antibodies, the illness is mild, and following infection, the baby develops their own, long-lasting immunity.
Dr. Puliyel and colleagues suggest that in the case of chickenpox, mothers develop sub-clinical viremia and the viral DNA is transferred to their babies. It is likely that in such cases, antibodies are developed actively in the fetus. The authors found antibody levels against chickenpox in new-born babies were often higher than that in mothers suggesting that the antibody was actively transported to the baby. The authors note that
- “Babies develop more long-lasting active immunity with the transfer of chickenpox DNA from mothers – more than the short-term passive protection provided by the transfer of readymade antibodies.“
In the absence of vaccines, chicken pox spreads easily in the population and repeated exposure to the virus acts like booster doses. The high antibody levels – much higher than that after vaccination – are passed to babies and it protects them. Vaccination on the other hand will reduce person to person spread of natural disease and the antibody titres are not boosted, and so there is little protection provided to the next generation.
The authors suggest that ‘Chickenpox parties’, whose aim is to get the children exposed to others with chickenpox is not necessarily a bad idea, inasmuch as the children get naturally infected in childhood, when the disease is typically mild. The immunity that young girls acquire from having the infection, will likely be passed on to their feus during pregnancy when Chickenpox antibodies and DNA emerge.
“These findings broaden our understanding of how man has evolved to coexist, survive and even thrive, with the microorganisms in the environment,” the authors say adding that government disease control plans with vaccines — for infections which are not considered lethal — have a potential to disturb this equilibrium. “This needs to be factored-in when embarking on global disease eradication programmes,” they caution.
*Disclosure: Dr. Jacob Puliyel is a member of the Distinguished Advisory Board of the Alliance for Human Research Protection.
The self-archived article [Epub ahead of print] is available here in accordance with the agreement of the authors with the publishers who hold copyrights to the article https://jacob.puliyel.com/download.php?id=446